Process for electroplating metal goods



May 26, 1925. 1,539,577

F. KIRSCHNER PROCESS FOR ELECTROPLATING METAL GOODS Filed Aug. 24. 1921 ATOMIZER FOR SPRR YING- ADHES ION FLUX HPPLN. FOR REMOVING FATTY Mrrzn 5y MILK 4 OFLIME 03 um: war: Fmvsuvo ,qppnnn-ru F 1 I P/cnup/b APPLN. cor 's m 8 PRESSURE flo Lsns 0F PICKLING BATH THROUGH wulcn' ELECTRIC cunmznn: 1:. PASSED MOVAL 0F EXCE S6 FUSION OR HOTAIR FURNACE 'I'O F'VSI 'THIZ D ILPOSYTSD METR ON TO GROUND METAL Fig. 2.

CLEANING RP LN.

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Patented May 26, 1925.

UNITED STATES OFFICE.

FELIX KIBSCHIIER, OFV'IEITNA AUSTRIA.

PROCESS FOR ELECTBOPLATING METAL GOODS."

Application filed August 24, 1921. Serial No. 494,870.

(GRANTED UNDER THE IPBOVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT, In, 1313.)

To all whom it may concern:

Be it known that I, FELIX Kmscnnnn, subject of the Republic of Switzerland, residing at Vienna, XVII, Hernalsergurtel N1. 1, Republic of Austria, have invented certain new and useful Improvements in Processes for Electroplat-ing Metal Goods (for which I have filed applications in Austria October 10, 1917: Germany, October 18,

1917; Hungary, October 16, 1917 Czecho slovakia, April 17, 1920; Switzerland, March 20. 1920; Belgium, November 6, 1920; Great Britain, Ma 13, 1920; France, June 30, 1920; Italy, J u y 16, 1920), of which the following is a specification.

Articles have hitherto been electroplated either by electrolysis alone in a suitable electrolytic bath or by electrolysis and subsequent fusing of the electrolytic coating on to the plated article. his well known that electroplating with certain metals as for instance tin, gives rise to many serious difficulties and that therefore the coating of articles with such metals must in practice inmost cases be effected in the old manner, that is to say by dipping, which is deficient in many respects. For overcoming these objections new compositions for the electrolytic bath as well as special methods for fusing the electrolytic deposit on to the goods have been proposed, for instance the use of hot grease baths of tallow or palm oil. It has also been proposed first to coat the metal article with a metal or alloy having a melting point lower than that of the metal wi h which the article is finally coated, and then by heating the article this intermediate layer of the readily fusible metal is caused to fuse and thereby causes the final coating to unite with the metal of the article itself hot-withstanding the w all known need for a process for coating metal goods with metals that will be commercially successful and secure an intimate and absolutely reliable adhesion of the coating metal to the metal of the articles to be plated and at the same time warrant a perfectly smooth and bright surface of the coating, free from pores, such a process has not yet been discovered.

Bythe methods heretofore proposed and employing grease baths, smooth coatings, free from pores, can only be obtained with the use of special and very complicated smoothing apparatus (pressure rollers, polishing rules. and the like). Apart from the fact that the passing of goods with a fused coating through smoothing devices presents great difliculties in practice, it will be understood that the'smoothing devices remove'ofnecessity so much of the fused coating metal that a reliable and durable protective coating cannot be obtained at all in this way. Nor does the use of readily fusible intermediate metal layers for intimately uniting the coating metal proper with the ground metal'furni'sh a commercially satisfactory coated article, because, the use of soldering fluxes being impossible, the intimate and reliable adhesion of the coating metal proper to the: ground metal cannot in practice be realized.

As a result of close investigation it has been found that the above difiiculties, which are particularly troublesome in tinning (for instance in the manufacture of tin plate) may be very effectively removed by the process forming the subject of the present invention. This consists essentially in coating the goods with metal by electrolytic deposition and treating them, before or during the fusing of the electrolytically deposited coating on to the ground meta l, with an adhesion flux, and in treating the coating when fused on to the ground metal, prefarably while warm, with water or aqueous solutions. orotherwise cooling the same so that smooth, bright, electroplated goods are obtained having a coating free from pores and capable of resisting the action of air and moisture. Y I

In the term adhesion fluxes any of the substances are included which, within the scope of the invention as hereinafter fully set forth, are capable of producing, by their reaction on the coating metal after the fusing of the same, in combination with. the subsequent cooling as by treatment with water or aqueous solutions, a smooth, bright coating, free from pores.

In order to more fully describe the improved process reference is made to the ac- .companying drawing illustrating, by Way of which may consist of a length of sheet iron either in the form of an endless band or of lengths connected b folds a so as to form an endless band.

. is band isled from a supply table 1 or a roller or the like, and is continuously fed by suitable feeding devices to the various parts of the plant in succession and, when finished, wound upon a winding drum or roller 20. The several apparatus of the plant are the following:

2 is a pair or set of pressure rollers serving. on t forward and on the other hand for ressing o'ut'or smoothin down the folds a2. etween the consecutive en s or sheets. 3 is any known or preferre apparatus for removing any fatty matter from the band, for instance by milk of lime or lime water. 4 is a rinsing apparatus which -frees the band from any impurities remaining after the removal of fatty matter. 5'is an electric pickling apparatus in which in well known manner the and is thoroughly ickled by means of a pickling bath through which an electric'current is passed. In order to make the band perfectly fit for electroplating, there may be Q interposed between the pickhng bath 5 and the electroplating cell 6 further apparatus (not shown in the drawings) well known in themselves for removing fatty matter for rinsing, brushing and again rinsin the band is, .by which means the cleaning of the 'band is completed. 6 is the electro lating bath. 7 is an elastic air of rollers by which the excessof li ui adhering to the "band after electrodeposition of the coatin is removed. 7 8, 8 isan atomizer, operated y air under -pressure; b which the adhesion. flux to be described urther'on is s 'rayed upon the to andunderside of -the and in a. finely an ivided state. h9 ,is*a s et of two pairs of rollers which are preferably covered with fabric and revolve slowly in the direction indicatedin the drawing and have for their object to distribute evenly thelayer of adhesionflux sprayed upon the band and to remove any local excess of the adhesion flux. 10, 11, '12 are guide rollers b I s'caused to run obliquely then. downwards in'a' part of its continuous movement. 13 is a fusing orhot airffuiinace of any known or preferred construc- 'tion, which serves'for fusing on the electro- I Y lytically depositedcoating metal onto the 2mg ground metal in the presence of theadhecoating re realized. 1 m be o w i ing apparatus of any known or preferred e one hand for feeding the band.

a solution of chloride 0 I which the band upwards and sion flux, which in the meanwhile has dried A 1,5aaa77 or aqueous solutions, which the band is cooled and at the; same time thoroughly treated with the said solution. 15 is a cleanconstruction. 16 is a rinsing apparatus of well known form. 17 are elastic rollers for removing water, 18 is a drying oven provided with a heatin device 18' and a draught pipe 18" in which drying discs 18" of some sultab'le fabric may be rovided. 19 is a wiping or drying device, y which the lustre of the coating fused on to the ound metal is completed, the} last impurlties still remaining on the bright coating being removed by this device. 20 is a roller on which the band may be wound; for this may be substituted an ap aratusfor cutting the finished band into s eets.

After the band :0 has passed through the pickling and electroplating apparatus it 3 comes in front of the atomizer 8, 8 which consists of'an: injector like atomizing nozzle of any suitable construction, b which liquids containing substances capa 1e of acting as adhesion fluxes may be finely sprayed on l to the hand. For the atomizer may be substituted any device which allows the band, to be supplied-with adhesion 'flux and the f quantitya'nd the distribution thereof to be nicel controlled. Applying the adhesion flux 1n the form of a fine powder by brush- 'ing and subse uently uniformly distributing the same by t e rufling orflwipin devices 9" has been found by experiment .to particularly advantageous. 1 Y As stated above the composition of the adhesion flux may vary. By way of example the following composition has been found by experiment to be highly eflicacious: 10 to 30' parts by weight of concentrated h drochloric acid; 10 to 40 farts by weig t of iron (30 to 0%)" I 20 to 40 parts by weight of aconcentr'ated solution of chloride of ammonia (sal am monia) 20 to 40 parts byweight of a solution of sulphate of copper (5 to 20%) or other copper salts. The object-and the op-' v eration'of the adhesion flux" (so far as under-. stood at present) will: be morefully explained later. The band then passes through the fusing or hot air furnace 13. In this furnace the galvanically deposited coating on the goods s fused "by the-hot air and the'llried adhesion flux ispartially split up. The bath 14 isarranged-c'lose ug to and m,rear of the heating-furnace inor watertreatment. .of the goods'.

, ate! n onthe fusing roc- The is'that the gooss'as eut of the'furnace are immediately "on lea furnace and are-freed- 21818. ail

th consists-Jeff} to w 'ch cold er to enable the coolhydrochloric acid) is led by a pipe; the overflowing of the bath 14 is prevented by the provision of one or more overflow pipes.

In the cleaning device 15 the goods or the band as are cleaned by weak basic solutions.

ing apparatus is quite unnecessary wlth the present process as the goods after being treated in the bath 14 already show a surprising polish and actually only require to be drie I As will be seen from the foregoing description of a plan which by way of exam le will serve to carry out the new process, t c said pr ocess consists in treating the electrolytically coated goods before or during fusing of the galvanically deposited coating with an adhesion flux and in subsequently treating in water or aqueous solutions the deposited coating preferably whilev warm which has been fused in the presence of the dried adhesion flux the goods being of course cooled at the same time. The term adhesion flux in the absence of exact scientific explana-' tion of what takes place in the present process is to be interpreted in the widest sense. It is essential that the adhesion flux used should be adapted when split up upon the fusion of the coating to cause a perfectly smooth adhesion free from pores. In other words the adhesion flux must be of such a nature that the fused coating on solidifying thoroug gl y intimately adheres to the ground metal and forms a bright surface free from any pores, as these condition are essential for the perfect protection of the ground metal against-the deleterious atmospheric action which is the main object of -the coating. The adhesion flux should preferably be of such a nature that the oxides formed on fusing the coating combine with the residues of the adhesion flux to form substances which are soluble in water and may be readily removed.

This requirement is fully satisfiedby the ad' hesion flux described above by way of example. The above mentioned property of the adhesion flux plays an important part in carrying into practice the above process inasmuch as it secures cheapness, economy of time and cleanliness, whereas in the processes heretofore known, inwhich grease baths ,are used, besides the smoothing apparatus very complicated and expensive cleaning apparatus had to be used for removing from the goods the residues of grease which harden durlng the process- Generally speaking it may be concluded from my investigations that all adhesion fluxes containing substances which readily decompose, as also adhesion fluxes disengaging chlorine at the fusing temperature of the coating metal, are suitable for the purpose hereinbefore described. 4

The addition of solutions of metal salts (for instance solutions of iron and copper salts) has been observed to promote greatly the effect aimed at. The explanation of this is possibly that by the addition of these metal salts and by the reaction of the ground metal on the said salts traces of fresh metal are deposited, which create on the coating metal as it were a fresh metal skin which is most readily acted upon chemically. This fresh metal skin then enhances the action of. the adhesion flux because the substances disengagedin the dissociation of the flux as is well known act much more intensely on fresh metal surfaces.

The process above described can be made applicable in all electrolytic thermic metal coating operations by varying the details in a manner obvious to persons conversant with the art.

I claim: x

1. The herein described process of improving the character of an electrolytically deposited coating of a comparatively easily fusible metal on a less easily fusible ground metal which consists in smelting the chating under the cooperation of an adhesion flux, and in artificially cooling the ground metal and the coating while the coating is still in molten condition, whereby the molten coating sets completely during the cooling operation.

2. The herein described process of smelting an electrolytically deposited coating of tin'onto a ground metal, which consists in smelting the coating of tin under the cooperation of an adhesion flux, then cooling 'the ground metal and the coating while the coating is still in molten condition by a liquid whereby the molten coating sets completely during the cooling operation and the residues of the adhesion flux are removed.

3. The herein described process of improving the character of an electrolytically deposited coating of a comparatively easily fusible metal on a less easily fusible ground metal which consists in smelting the coating under the cooperation of an adhesion .flux comprising readily dissociable substances and metal salts, and capable of precipitating its metal upon the electrolytically deposited coating, and in cooling the ground metal and the coating while the coating is still in molten condition whereby the molten V coating sets completely during the cooling operation.

4. The herein described process of smelt ing an electrolytically deposited coating of completely during the cooling operation.

5. The herein described process of smelting an electrolytically deposited coating of tin onto a ground metal which consists in smelting the coating of tin under the cooperation of an adhesion flux comprising readily dissociable substances and metal salts and capable of precipitating its metal upon the electrolytically .deposited coating,

and in cooling the ground metal and the coating while the coating is still in molten condition whereby the molten coating sets completely during the cooling operation.

6. The herein described process of smelting an electrolytically deposited coating of tin onto a ground metal which consists in smelting the coating of tin under the cooperation of an adhesion fluxcomprising water, hydrochloric acid, chloride of am- Inonia, chloride of iron and sulphate of copper, and in cooling the ground metal and the coating while the coating is still in molten condition whereby the molten coating -sets completely during the cooling operation. x

' 7. The herein described process of smelting an electrolytically deposited coating of tin onto a ground metal which consists in smelting the coating of tin under the co- 1 operation of an adhesion flux comprising ing sets completely during the cooling operation.

10 to parts by weight of concentrated hydrochloric acid, 10 to parts by weight of a 30 to aqueous solution of iron chloride, 20 to 40 parts by weight 'of a concentrated aqueous solution, of ammonium chloride and 20 to 40 parts by weight of a 5 to 20% aqueous solution of copper sul-- phate, and in cooling the ground metal and the coating while the coating is still in molten condition whereby the molten coat- 8. The herein described process of smelt- :ingan electrolytically deposited coating of a comparatively easily fusible metal onto a less easily fusible ground metal which consists in smelting the coating under the cooperation of an adhesion flux, and in cooling the ground metal and the coating ina water-bath while the coating 1 is still in molten condition.

9. The herein described process of smelting an electrolytically deposited coating of tin onto a ground metal which consists in smelting the coating of tin under the cooperation of an adhesion flux, and cooling the ground metal and, the coating in a watertion of an adhesion flux, andiin cooling the ground metal and the coating in a bath containing acid diluted water while the coating is still in molten condition.

11. The herein described rocess of smelting an electrolytically deposited coating of a comparatively easily fusible metal onto a ground metal which consists in uniformly.

applying to and distributing on the coating predetermined quantities of an adhesion flux, smelting the coating with the cooperation of the adhesion flux, and in cooling the ground metal and the coating while the chating is still in molten condition whereby the molten coating sets during the cooling operation. I

- .12. The herein described process of smelting an electrolytically deposited coating of a comparatively easily fusible metal onto a a ground metal which consists in spraying an aqueous solution of an adhesion flux onto the electrolytically deposited coat1ng,.smelting the coating with the cooperation of an adhesion flux, and in cooling the ground metal and the coating while the coating is still in molten condition whereby the molten coating sets during the cooling operation.

13 The herein described process of smelting an electrolytically deposited coating of a comparatively easily fusible metal onto a. ground metal which consists in smelting the coating under the cooperation of an adhesion flux by means of hot'air, and in cooling the ground metal and the coating while the coating is still in molten conditlon whereby the molten coating sets completely during the cooling'operation.

14. In the process of improving the character. of an easily fusible metalcoatlng electrolytically deposited on a less easily fusible und metal, the step of simultaneously smelting the coating and reducing its normal surface tension, and the further step of artificially cooling the coated metal to completelyset the coating.

In testimony whereof I afiix my signature.

FELIX KIRSCHNER. 

